The present invention relates to a cleaning liquid for semiconductor devices and a cleaning method. More specifically, the present invention relates to a process of manufacturing semiconductor devices and particularly to a cleaning liquid for removing a photoresist, an etching residue, an antireflective film, and an ashing residue which are present on a substrate in the whole process of semiconductor device manufacture, as well as a method of cleaning semiconductor devices using the cleaning liquid.
Semiconductor devices such as CCDs and memories are manufactured by forming fine electronic circuit patterns on substrates using photolithographic technology. Specifically, such semiconductor devices are manufactured by a process which involves forming on a substrate a laminate film including a film of a metal (e.g., copper) serving as a wiring material, an interlayer dielectric film and an antireflective film, applying a resist film onto the laminate film and carrying out a photolithographic step and a dry etching step. The photoresist and the antireflective film remaining following the photolithographic step are subjected to dry ashing. Thereafter, a treatment is commonly performed in which residues (e.g., etching residue and ashing residue) that were generated by the dry etching step and the dry ashing step and remain on the wiring material and interlayer dielectric film material are removed with a cleaning liquid.
Increased performance of semiconductor devices has created a need in recent years for further miniaturization and higher manufacturing speeds. Under the circumstances, shortening of the cleaning time in the process of manufacturing the semiconductor devices and improvement of the cleaning technology are important issues. For example, interlayer dielectric films made of low-k materials are used in order to improve the performance of the semiconductor devices. In cases where the low-k materials have pores due to a decrease in the k value, the presence of the pores may increase the contact area between the cleaning liquid and the low-k materials during the cleaning step, thus causing the low-k materials to be etched by the cleaning liquid during the cleaning step. This brings about a change in the shape of the device wiring, which is not preferable for the device performance.
With the thinner wiring and higher performance of the semiconductor devices, the manufacturing process has recently shifted to one in which no dry ashing step is carried out or a dry ashing step is moderately carried out in order to reduce damage to the interlayer dielectric films made of wiring materials and in particular low-k materials during the manufacturing process. Therefore, a cleaning liquid capable of thoroughly removing the photoresist and the antireflective film without performing the dry ashing step or the like has been desired.
For example, cleaning liquids comprising a mixture of an alkanolamine and an organic solvent have conventionally been proposed for the semiconductor device-cleaning liquid for use in removing the above-described photoresist, antireflective film, etching residue and ashing residue (see JP 62-49355 A and JP 64-42653 A). U.S. Pat. No. 5,279,771 discloses a cleaning liquid comprising an alkanolamine, hydroxylamine, catechol and water.
U.S. Pat. No. 5,185,235 discloses a cleaning liquid comprising an alcoholic solvent, a halogenated solvent and an organic quaternary ammonium salt.
U.S. Pat. No. 5,466,389 discloses a cleaning liquid comprising water, tetramethyl ammonium hydroxide, hydrogen peroxide, and a nonionic surfactant.
US 2007/099810 A1 discloses a cleaning liquid comprising sodium hydroxide or potassium hydroxide, a water-soluble organic solvent, and a corrosion inhibitor of a group IX or XI metal.